1. Field of the Invention
The present invention relates to a medical apparatus, especially to a syringe having a function that safely controls the injection dose and a function that is laborsaving in operation.
2. Description of Related Art
In order to achieve multiple purposes such as dose metering, injection time counting, and repeatable using, the conventional syringes include two kinds: a dose metering syringe and a frequency measuring syringe. The structure of the conventional dose metering syringe mainly includes a driving device assembled by multiple driving components mounted in a barrel and connected with a piston rod. A vial is assembled in the barrel. A needle is mounted on a front end of the barrel and is connected with the vial for injecting. When the syringe is in an injecting process, the needle is pierced into the skin or the veins of a human body, the driving device is driven by pushing the piston rod to inject the medication. The dose of the injection can be controlled by the driving device and the movement of the piston rod to achieve the purpose of dose-metering.
Although the dose metering syringe already achieves the purpose of dose-metering, the dose metering syringe still has a laborious issue because the components of the driving device restrict the movement of each other and the driving device requires a lot of effort to use.
To overcome the shortcomings of the conventional dose metering syringe, the present invention provides a syringe to mitigate or obviate the aforementioned problems.